High temperature hydrator

ABSTRACT

A method includes transferring at least one feed stream including calcium oxide, calcium carbonate, water, and a fluidizing gas into a fluidized bed; contacting the calcium oxide with the water; based on contacting the calcium oxide with the water, initiating a hydrating reaction; producing, from the hydrating reaction, calcium hydroxide and heat; transferring a portion of the heat of the hydrating reaction to the calcium carbonate; and fluidizing the calcium oxide, calcium hydroxide, and the calcium carbonate into a first fluidization regime and a second fluidization regime. The first fluidization regime includes at least a portion of the calcium carbonate and at least a portion of the calcium oxide, and the second fluidization regime includes at least a portion of the calcium hydroxide and at least another portion of the calcium oxide. The first fluidization regime is different than the second fluidization regime.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to U.S.Provisional Patent Application Ser. No. 62/334,225, entitled “HighTemperature Hydrator,” and filed on May 10, 2016, the entire contents ofwhich are incorporated by reference herein.

TECHNICAL FIELD

This disclosure describes systems, apparatus, and methods for convertingcalcium oxide to calcium hydroxide.

BACKGROUND

Calcium oxide conversion to calcium hydroxide has been described, inwhich calcium oxide is reacted with water to produce either a fine, drypowder of calcium hydroxide or a slurry of calcium hydroxide in water.The resulting calcium hydroxide is used in calcium based causticrecovery processes such as the Kraft caustic recovery process employedby the pulp and paper industry.

SUMMARY

In an example implementation, a method includes transferring at leastone feed stream including calcium oxide calcium carbonate, water, and afluidizing gas into a fluidized bed; contacting the calcium oxide withthe water; based on contacting the calcium oxide with the water,initiating a hydrating reaction; producing, from the hydrating reaction,calcium hydroxide and heat; transferring a portion of the heat of thehydrating reaction to the calcium carbonate; and fluidizing the calciumoxide, calcium hydroxide, and the calcium carbonate into a firstfluidization regime and a second fluidization regime. The firstfluidization regime includes at least a portion of the calcium carbonateand at least a portion of the calcium oxide, and the second fluidizationregime includes at least a portion of the calcium hydroxide and at leastanother portion of the calcium oxide. The first fluidization regimebeing different than the second fluidization regime.

In an aspect combinable with the example implementation, the secondfluidization regime includes another portion of the calcium carbonate.

In another aspect combinable with any of the previous aspects,fluidization takes place using at least one fluidization velocity, theat least one fluidization velocity sufficient to cause the at least aportion of one of the calcium carbonate, calcium hydroxide or calciumoxide to separate from the at least a portion of the other calciumcarbonate, calcium hydroxide or calcium oxide into the first and secondfluidization regime.

In another aspect combinable with any of the previous aspects, the firstand second fluidization regimes include a bubbling bed regime and atleast one of a transport or turbulent regime.

Another aspect combinable with any of the previous aspects furtherincludes transferring at least a portion of the heat to the calciumcarbonate.

Another aspect combinable with any of the previous aspects furtherincludes fluidizing at least a portion of the calcium carbonate in thebubbling bed regime; and fluidizing at least a portion of the calciumhydroxide in the transport or turbulent fluidization regime.

In another aspect combinable with any of the previous aspects, thefluidizing gas includes steam.

Another aspect combinable with any of the previous aspects furtherincludes recirculating a portion of at least one of the calcium oxide orthe calcium hydroxide in the transport or turbulent fluid regime backinto the fluidized bed; and based on the recirculating, increasing aresidence time of at least one of the calcium oxide or calcium hydroxidein the fluidized bed.

Another aspect combinable with any of the previous aspects furtherincludes generating steam from excess heat; and circulating thegenerated steam to provide heat or power to the at least one of adownstream heat consumer or power producers.

Another aspect combinable with any of the previous aspects furtherincludes providing the water from at least one of a steam feed, a liquidwater feed, or water from a wet calcium carbonate feed.

Another aspect combinable with any of the previous aspects furtherincludes recirculating the fluidization gas that exits a fluidized gasoutlet of the fluidized bed to a fluidization gas inlet of the fluidizedbed.

In another aspect combinable with any of the previous aspects, themethod is part of a caustic recovery process.

In another aspect combinable with any of the previous aspects, thecaustic recovery process is part of at least one of a direct air captureprocess, a carbon dioxide capture process, or a pulp and paper process.

In another aspect combinable with any of the previous aspects, at leasta portion of one of calcium carbonate, calcium oxide or calciumhydroxide are separated into at least two different fluidization regimesbased on one or more of physical properties of the calcium carbonate,calcium oxide, or calcium hydroxide.

In another aspect combinable with any of the previous aspects, the oneor more physical properties includes at least one of density, particlesize or shape.

Another aspect combinable with any of the previous aspects furtherincludes at least one of heating or drying the calcium carbonate with atleast one of a sensible heat of the calcium oxide or the produced heatof the hydrating reaction.

In another aspect combinable with any of the previous aspects, each ofthe calcium oxide, the calcium carbonate, the water, and the fluidizinggas are transferred into the fluidized bed in a separate feed stream.

In another aspect combinable with any of the previous aspects, thecalcium oxide and at least a portion of at least one of the water or thefluidizing gas are transferred into the fluidized bed in a first fluidstream, and the calcium carbonate and at least a portion of at least oneof the water or the fluidizing gas are transferred into the fluidizedbed in a second fluid stream that is separate from the first fluidstream.

In another example implementation, an apparatus includes a fluidized bedvessel that includes one or more inlet ports arranged to receive atleast one feed stream including calcium oxide, calcium carbonate, water,and a fluidizing gas into a volume of the fluidized bed vessel, thefluidized bed vessel including a zone where the calcium oxide contactsthe water to initiate a hydrating reaction to produce calcium hydroxideand heat, the fluidized bed vessel configured to operate with afluidization velocity that fluidizes and separates at least a portion ofthe calcium carbonate and at least a portion of the calcium oxide into afirst fluidization regime, and at least a portion of the calciumhydroxide and at least another portion of the calcium oxide into asecond fluidization regime, the first fluidization regime different thanthe second fluidization regime; a heat transfer assembly thermallycoupled to the fluidized bed vessel and configured to transfer a portionof the heat of the hydrating reaction to the calcium carbonate; acyclone fluidly coupled to the fluidized bed vessel and configured toseparate a portion of the fluidization gas from a portion of at leastone of the calcium hydroxide, calcium carbonate or calcium oxide; and anoutlet port configured to separate the fluidization gas from a portionof at least one of the calcium hydroxide, calcium carbonate or calciumoxide, and to discharge a portion of at least one of the calciumhydroxide, calcium carbonate or calcium oxide.

In an aspect combinable with the example implementation, the fluidizedbed vessel is configured to contain a bubbling bed regime and allows forat least one of a circulating turbulent or transport regime.

Another aspect combinable with any of the previous aspects furtherincludes a solids classifier fluidly coupled to the fluidized bed vesseland the outlet port, the solids classifier configured to separate aportion of at least one of the calcium carbonate, calcium hydroxide orcalcium oxide from another portion of at least one of the calciumcarbonate, calcium hydroxide or calcium oxide.

In another aspect combinable with any of the previous aspects, the heattransfer assembly is configured to transfer a portion of a heatcontained in the calcium oxide feed stream to the calcium carbonate.

In another aspect combinable with any of the previous aspects, thebubbling bed regime includes calcium carbonate and at least one of atransport or turbulent regime including calcium hydroxide.

In another aspect combinable with any of the previous aspects, thefluidized bed vessel is configured to operate with a fluidizing gasincluding steam.

In another aspect combinable with any of the previous aspects, thecyclone further includes a port fluidly coupled to a non-mechanicalseal, the non-mechanical seal fluidly coupled to the fluidized bedvessel and configured to recirculate at least a portion of one ofcalcium carbonate, calcium hydroxide or calcium oxide in the transportor turbulent fluid regime back into the fluidized bed vessel.

In another aspect combinable with any of the previous aspects, thenon-mechanical seal includes a loop seal.

In another aspect combinable with any of the previous aspects, the atleast one feed stream includes liquid water, the heat transfer assemblyconfigured to transfer heat from the fluidized bed vessel to the liquidwater to generate a steam stream.

In another aspect combinable with any of the previous aspects, in theheat exchange assembly includes a heat tubing system thermally coupledto the fluidization bed vessel, the heat tubing system configured totransfer a portion of a heat from the fluidization bed vessel to a fluidstream within the heat tubing system.

In another aspect combinable with any of the previous aspects, theapparatus is thermally and fluidly coupled to a dense fluidized bed heatexchanger.

In another aspect combinable with any of the previous aspects, thecyclone further includes a fluidly coupled port that is configured toenable the fluidization gas to recirculate back to the fluidization gasinlet port.

In another aspect combinable with any of the previous aspects, the solidclassifier is configured to separate at least a portion of the calciumcarbonate from a portion of at least one of the calcium hydroxide or thecalcium oxide based on at least one of particle size or particledensity.

In another aspect combinable with any of the previous aspects, the solidclassifier is configured to allow the at least one of calcium hydroxideor calcium oxide to return to the fluidized bed vessel.

In another aspect combinable with any of the previous aspects, the solidclassifier includes a cone and cap sloped stripper or a sieve.

In another aspect combinable with any of the previous aspects, theapparatus is fluidly coupled to a caustic recovery process.

In another aspect combinable with any of the previous aspects, thecaustic recovery process includes a direct air capture process, a carbondioxide capture process or a pulp and paper process.

In another aspect combinable with any of the previous aspects, the atleast one feed stream including calcium oxide, calcium carbonate, water,or a fluidizing gas further includes sensible heat, and the heattransfer assembly is configured to transfer at least a portion of thesensible heat to the calcium carbonate to enable at least one of heatingor drying of the calcium carbonate.

In another aspect combinable with any of the previous aspects, each ofthe calcium oxide, the calcium carbonate, the water, and the fluidizinggas are transferred into the fluidized bed in a separate inlet port.

In another aspect combinable with any of the previous aspects, thecalcium oxide and at least one of at least a portion of the water or aportion of the fluidizing gas are transferred into the fluidized bed ina first inlet port, and the calcium carbonate and at least one of atleast a portion of the water or a portion of the fluidizing gas aretransferred into the fluidized bed in a second inlet port that isseparate from the first inlet port.

Implementations according to the present disclosure may include one ormore of the following features. For example, this system includesmultiple components, for example dryer, hydrators and heat exchangecomponentry, in a single unit. In some aspects, conventional componentsfor hydrating processes, such as a dryer, hydrator and heat exchangeequipment, are replaced by one fluidized bed reactor. The fluidized bedreactor unit has no moving parts, and as such has lower maintenance thansystems with separate hydrator, dryer and heat exchanger units, whichcan require for example transport and/or conveying equipment (withmoving parts). The high temperature fluidized bed hydrator unit hashigher thermal efficiency than the previously separated equipment, dueto having the process streams in direct contact with heat sources (forexample, other process streams, fluidizing gases). By using processstreams in this manner, the multiple approach temperatures associatedwith separate heat exchangers can be reduced, for example, from multipleapproaches to a single approach. Furthermore, the steam produced withinthe high temperature hydrator unit can be used in other areas of aplant, for example to provide heat or steam for power generation. Thisaids in improving overall energy efficiencies of the systems withinwhich a high temperature hydrator may operate.

The details of one or more implementations of the subject matterdescribed in this disclosure are set forth in the accompanying drawingsand the description below. Other features, aspects, and advantages ofthe subject matter will become apparent from the description, thedrawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed.

FIG. 2 depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed and an optional waterinjection system.

FIG. 3A depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed, where circulating materialmay be recirculated.

FIG. 3B depicts another illustrative system for converting calcium oxideto calcium hydroxide including a fluidized bed, where circulatingmaterial may be recirculated.

FIG. 4A depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed, where material dischargedfrom the bed is further processed.

FIG. 4B depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed, where material may beseparated before being discharged.

FIG. 5A depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed and a system for indirectlytransferring heat.

FIG. 5B depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed and a system for indirectlytransferring heat.

FIG. 6 depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed and a system for indirectlytransferring heat.

FIG. 7 depicts an illustrative system for converting calcium oxide tocalcium hydroxide including a fluidized bed connected with anothersystem.

DETAILED DESCRIPTION

The present disclosure describes example implementations of a hightemperature hydrator system that may enable two or more solid feedstocksand any resulting solid reaction products to separate into twodistinctly different fluidization regimes, based on the different solidphysical properties, such as density, particle size distribution andshape. For example, a portion of the feedstocks and a portion of theresulting reaction products, consisting of, for example, more denseparticles, larger particles and/or particles of a geometry, which, inthe given fluidization environment, favor a bubbling bed regime, whileanother portion of the feedstocks and reaction products, consisting forexample of less dense particles, smaller particles, and/or particles ofa geometry, which, in the given fluidization environment, favor aturbulent or transport regime. Regimes of fluidization may result fromthe fact that fluidized solid beds behave differently as gas properties,velocity, and solid properties are varied. For example, when a solid bed(having a defined set of solid properties) is exposed to an upwardflowing fluid, such as a gas (having a defined set of fluid properties),a pressure drop develops across the bed. As the upward flow rate of thefluid increases, there are a range of fluidization regimes that maydevelop.

One example of a distinct fluidization regime is the bubbling bedregime. A bubbling bed regime is one where the solid material isfluidized above the material's incipient fluidization point but belowthe point where the material becomes entrained in the gas and capable ofleaving the reactor with the gas flow. Another example of a distinctfluidization regime is a turbulent, or transport regime. The turbulentor transport regime is one where the solid material is fluidized to thepoint where the material becomes entrained in the gas and is transportedout of the reactor with the gas. Other examples of distinct fluidizationregimes seen in fluidized bed reactors may include homogeneous, densesuspension upflow, slugging, spouted bed, turbulent, fast fluidizing,and pneumatic transport.

In addition to fluidizing the solids, this system provides a desirableenvironment to allow for the hydrating reaction to occur, wherebyincoming calcium oxide mixes with water, in the form of liquid and/orsteam, to produce calcium hydroxide. The sensible heat from some of thehot solid feed material, as well as the heat generated from thehydrating reaction itself are used to dry and preheat the other cooler,moist solid materials. Both the hydrating reaction and the heat transferprocesses take place in a fluidized bed reactor vessel wherein solidcalcium carbonate, solid calcium oxide, steam and liquid water come intocontact.

This system includes multiple components, for example dryer, hydratorsand heat exchange componentry, in a single unit. In some aspects,conventional components for hydrating processes, such as a dryer,hydrator and heat exchange equipment, are replaced by one fluidized bedreactor. This resulting high temperature fluidized bed hydrator unit hashigher thermal efficiency than the previously separated equipment, dueto having the process streams in direct contact with heat sources (forexample, other process streams, fluidizing gases). By using processstreams in this manner, the desired multiple approach temperaturesassociated with separate heat exchangers are also reduced, for example,from multiple approaches to a single approach. The fluidized bed reactorunit has no moving parts, unlike conventional hydrator and dryer units,and as such, has lower maintenance than such conventional units.

Each of the configurations described later may include process streams(also called “streams”) within a system for converting calcium oxide tocalcium hydroxide including a fluidized bed. The process streams can beflowed using one or more flow control systems implemented throughout thesystem. A flow control system can include one or more flow pumps to pumpthe process streams, one or more flow pipes through which the processstreams are flowed and one or more valves to regulate the flow ofstreams through the pipes.

In some implementations, a flow control system can be operated manually.For example, an operator can set a flow rate for each pump and set valveopen or close positions to regulate the flow of the process streamsthrough the pipes in the flow control system. Once the operator has setthe flow rates and the valve open or close positions for all flowcontrol systems distributed across the system for converting calciumoxide to calcium hydroxide, the flow control system can flow the streamsunder constant flow conditions, for example, constant volumetric rate orother flow conditions. To change the flow conditions, the operator canmanually operate the flow control system, for example, by changing thepump flow rate or the valve open or close position.

In some implementations, a flow control system can be operatedautomatically. For example, the flow control system can be connected toa computer or control system (e.g., control system 999) to operate theflow control system. The control system can include a computer-readablemedium storing instructions (such as flow control instructions and otherinstructions) executable by one or more processors to perform operations(such as flow control operations). An operator can set the flow ratesand the valve open or close positions for all flow control systemsdistributed across the facility using the control system. In suchimplementations, the operator can manually change the flow conditions byproviding inputs through the control system. Also, in suchimplementations, the control system can automatically (that is, withoutmanual intervention) control one or more of the flow control systems,for example, using feedback systems connected to the control system. Forexample, a sensor (such as a pressure sensor, temperature sensor orother sensor) can be connected to a pipe through which a process streamflows. The sensor can monitor and provide a flow condition (such as apressure, temperature, or other flow condition) of the process stream tothe control system. In response to the flow condition exceeding athreshold (such as a threshold pressure value, a threshold temperaturevalue, or other threshold value), the control system can automaticallyperform operations. For example, if the pressure or temperature in thepipe exceeds the threshold pressure value or the threshold temperaturevalue, respectively, the control system can provide a signal to the pumpto decrease a flow rate, a signal to open a valve to relieve thepressure, a signal to shut down process stream flow, or other signals.

Referring to FIG. 1, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 100. In some implementations, system 100 may include feed portsfor streams 101, 102 and 105 fluidly coupled to the main system 100, anda discharge port for stream 104 fluidly coupled to the main system 100.In some aspects a gas distribution plate 106 may be fluidly coupled tothe main vessel body of system 100. In some aspects system 100 mayinclude a cyclone 111 fluidly coupled to feed ports for stream 109 anddischarge ports for streams 112, 110. In some aspects system 100 mayinclude a control system 999 coupled to the components (illustrated orotherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 1, gaseous stream 102 includingone or more fluidization gases is provided to the hydrator system 100through the bottom entry zone 113, also known as the plenum chamber,which is below the fluidization distribution plate 106. Gaseous stream102 may be, for example, air, steam or a combination of these gases andtheir sub-components. Stream 101 is one of the solid feedstocks, whichenters the system above the fluidization distribution plate 106 andbecomes fluidized in the bed or bubbling bed regimes within thefluidized bed system 100 and as such it remains in the bubbling bed zone107, unless discharged as stream 104. Stream 101 may, for example,consist mostly of calcium carbonate or calcium oxide, and may alsoconsist in part of aqueous solutions such as liquid water. Stream 105 isthe solid feedstock which becomes fluidized in the turbulent ortransport fluidization regime and it also enters the system above thedistribution plate 106. Stream 105 may, for example, consist mostly ofcalcium oxide or calcium carbonate and may also consist in part ofliquid or gaseous water. The distribution plate 106 is designed toprevent backflow of any solids into the fluidization gas entry zone 113.Solid material 105, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 107 and transported through the reactorfreeboard zone 108. The resulting mixed stream of fluidization gases andsolids is mixed-stream 109, and after leaving the reactor freeboard zone108, the stream 109 is sent to a cyclone 111, to separate the solids112, from the gases 110. The fluidization gas 102, is blown into thefluidization gas entry zone 113, of the fluidized bed reactor 100. Thisfluidizing gas 102, could be partially recycled from the gas stream 110leaving the cyclone 111.

The hydrating reaction, where calcium oxide is converted to calciumhydroxide, takes place within the fluidized bed reactor system 100:CaO(s)+H₂O(l)→Ca(OH)₂(s) hydrating reaction using liquid water.CaO(s)+H₂O(g)→Ca(OH)₂(s) hydrating reaction using steam.

In some cases the water required for the hydrating reaction can besupplied into system 100 through excess steam brought in with stream102, or it could also be brought into the system 100 as part of thesolids material requiring heating/drying, via stream 101 or 105. In somecases, the stream requiring heat transfer (and that may contain liquidwater) could be either stream 101 or 105, depending on the application.For example, in a Kraft caustic recovery system, the calcium carbonatematerial may be introduced as smaller particles, which may be morecomparable to lime mud in particle size, while the calcium oxidematerial may be introduced as larger particles or clumps, and could havesizes closer to approximately one (1) centimeter in diameter.

In some implementations, a portion of the material normally fluidizedwithin the turbulent/transport regime may leave with the material in thebubbling bed regime. In these implementations, it can be separated basedon the difference in physical properties and re-introduced into thereactor system 100 or combined with the finished circulating solidsstream 112.

In some implementations, the system 100 could be heat insulated with,for example insulation material. In these cases, care would need to betaken in selecting both the insulation material for heat economy, aswell as the vessel material of construction. In some aspects, metalcompositions that are capable of maintaining structural integrity underoperating pressures and temperatures of around 300° C. would beselected, for example stainless steel or other metal compositions.

In another implementation, system 100 could instead be insulated withrefractory lining, allowing for more economical options for vesselmaterial of construction, for example carbon steel.

Referring to FIG. 2, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 200. In some implementations, system 200 may include feed portsfor streams 201, 202, 205 and 214 fluidly coupled to the main system200, and a discharge port for stream 204 fluidly coupled to the mainsystem 200. In some aspects a gas distribution plate 206 may be fluidlycoupled to the main vessel body of system 200. In some aspects system200 may include a cyclone 211 fluidly coupled to feed ports for stream209 and discharge ports for streams 212, 210. In some aspects system 200may include a control system 999 coupled to the components (illustratedor otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 2, gaseous stream 202 includingone or more fluidization gases is provided to the hydrator system 200through the bottom entry zone 213, also known as the plenum chamber,which is below the fluidization distribution plate 206. Gaseous stream202 may be, for example, air, steam or a combination of these gases andtheir sub-components. Stream 201 is one of the solid feedstocks, whichenters the system above the fluidization distribution plate 206 andbecomes fluidized in the bed or bubbling bed regimes within thefluidized bed system 200 and as such it remains in the bubbling bed zone207, unless discharged as stream 204. Stream 201 may, for example,consist mostly of calcium carbonate or calcium oxide, and may alsoconsist in part of aqueous solutions such as liquid water. Stream 205 isthe solid feedstock which becomes fluidized in the turbulent ortransport fluidization regime and it also enters the system above thedistribution plate 206. Stream 205 may, for example, consist mostly ofcalcium oxide or calcium carbonate and may also consist in part ofliquid or gaseous water. The distribution plate 206 is designed toprevent backflow of any solids into the fluidization gas entry zone 213.Solid material 205, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 207 and transported through the reactorfreeboard zone 208. The resulting mixed stream of fluidization gases andsolids is mixed-stream 209, and after leaving the reactor freeboard zone208, the stream 209 is sent to a cyclone 211, to separate the solids212, from the gases 210. The fluidization gas 202, is blown into thefluidization gas entry zone, 213, of the fluidized bed reactor, 200.This fluidizing gas 202, could be partially recycled from the gas stream210 leaving the cyclone 211. A portion of the water required for thehydrating reaction can be supplied into system 200 through a variety offeed methods including excess steam brought in with stream 202, as adirect, separate spray of liquid water, 214, which could be fed intoeither the bubbling bed 207 or freeboard zone 208, or a combination ofthese methods.

Referring to FIG. 3A, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 300. In some implementations, system 300 may include feed portsfor streams 301, 302, and 305 fluidly coupled to the main system 300,and a discharge port for stream 304 fluidly coupled to the main system300. In some aspects a gas distribution plate 306 may be fluidly coupledto the main vessel body of system 300. In some aspects system 300 mayinclude a cyclone 311 fluidly coupled to feed ports for stream 309 anddischarge ports for streams 312, 310. In some aspects the cyclonedischarge port for stream 312 is fluidly coupled back to the main bodyof system 300, and may include a non-mechanical valve and feed port onthe main body for recirculation of stream 315 back into the main bodyand a discharge port for stream 316. In some aspects system 300 mayinclude a control system 999 coupled to the components (illustrated orotherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 3A, gaseous stream 302including one or more fluidization gases is provided to the hydratorsystem 300 through the bottom entry zone 313, also known as the plenumchamber, which is below the fluidization distribution plate 306. Gaseousstream 302 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 301 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 306 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 300 and as such it remains in thebubbling bed zone 307, unless discharged as stream 304. Stream 301 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 305 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 306. Stream 305 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 306 is designedto prevent backflow of any solids into the fluidization gas entry zone313. Solid material 305, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 307 and transported through the reactorfreeboard zone 308. The resulting mixed stream of fluidization gases andsolids is mixed-stream 309, and after leaving the reactor freeboard zone308, the stream 309 is sent to a cyclone 311, to separate the solids312, from the gases 310. The fluidization gas 302, is blown into thefluidization gas entry zone, 313, of the fluidized bed reactor, 300.This fluidizing gas 302, could be partially recycled from the gas stream310 leaving the cyclone 311. A portion of the solid stream 312 leavingthe cyclone 311 is recycled back into system 300 as stream 315. Ifadditional residence time is required for the solids being dischargedfrom the cyclone 311, these solids can be fully or partiallyre-introduced back into the fluidization vessel of system 300, viastream 315, for example, in a similar fashion to that of a circulatingfluidized bed reactor. In some aspects, stream 315 can be re-introducedinto the fluidization vessel of system 300 by means of a non-mechanicalvalve. Some examples of non-mechanical valves are L-valves, J-valves,V-valves, loop seals, seal pots, reverse seals and the like. Stream 316can be used to withdraw a portion of the circulating solid material fromsystem 300.

Referring to FIG. 3B, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 300. In some implementations, system 300 may include feed portsfor streams 301, 302, and 305 fluidly coupled to the main system 300,and a discharge port for stream 304 fluidly coupled to the main system300. In some aspects a gas distribution plate 306 may be fluidly coupledto the main vessel body of system 300. In some aspects system 300 mayinclude a cyclone 311 fluidly coupled to feed ports for stream 309 anddischarge ports for streams 312, 310. In some aspects the cyclonedischarge port for stream 312 is fluidly coupled back to the main bodyof system 300, and may include a non-mechanical valve such as a loopseal 317 fluidly coupled to a feed port on the main body forrecirculation of stream 315 back into the main body and a discharge portfor stream 316. In some aspects system 300 may include a control system999 coupled to the components (illustrated or otherwise). In someaspects the loop seal 317 is fluidly coupled to a distribution plate 319and feed port for stream 318.

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 3A, gaseous stream 302including one or more fluidization gases is provided to the hydratorsystem 300 through the bottom entry zone 313, also known as the plenumchamber, which is below the fluidization distribution plate 306. Gaseousstream 302 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 301 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 306 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 300 and as such it remains in thebubbling bed zone 307, unless discharged as stream 304. Stream 301 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 305 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 306. Stream 305 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 306 is designedto prevent backflow of any solids into the fluidization gas entry zone313. Solid material 305, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 307 and transported through the reactorfreeboard zone 308. The resulting mixed stream of fluidization gases andsolids is mixed-stream 309, and after leaving the reactor freeboard zone308, the stream 309 is sent to a cyclone 311, to separate the solids312, from the gases 310. The fluidization gas 302, is blown into thefluidization gas entry zone, 313, of the fluidized bed reactor 300. Thisfluidizing gas 302, could be partially recycled from the gas stream 310leaving the cyclone 311.

A portion of the solid stream 312 leaving the cyclone 311 is recycledback into system 300 as stream 315. If additional residence time isrequired for the solids being discharged from the cyclone 311, thesesolids can be fully or partially re-introduced back into thefluidization vessel of system 300, via stream 315, for example, in asimilar fashion to that of a circulating fluidized bed reactor. In someaspects, stream 315 can be re-introduced into the fluidization vessel ofsystem 300 by means of a non-mechanical valve.

Some examples of non-mechanical valves are L-valves, J-valves, V-valves,loop seals, seal pots, reverse seals and the like. Stream 316 can beused to withdraw a portion of the circulating solid material from system300. All components in the system 300 are substantially the same as inthe embodiment of the system 300 illustrated in FIG. 3A, with theexception being that more detail is shown on how the system 300 could bebuilt to accommodate the recirculation of solid stream 312. In thisimplementation, solid stream 312 is shown moving down a vertical lengthof pipe that connects the cyclone 311 back to the main vessel body ofsystem 300. In some example aspects, this pipe may include anon-mechanical valve, such as a loop seal 317 complete with a gas stream318 being fed through a distribution plate 319. In some aspects thedistribution plate 319 may instead be nozzles. In some aspects the gasstream 318 may for example include air, steam or the like. Stream 318provides sufficient backpressure through the loop seal 317 so thatfluidizing gases from the main vessel system 300 do not divert backwardsthrough the loop seal 317.

Referring to FIG. 4A, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 400. In some implementations, system 400 may include feed portsfor streams 401, 402, and 405 fluidly coupled to the main system 400,and a discharge port for stream 404 fluidly coupled to the main system400. In some aspects the discharge port 404 is fluidly coupled to asolids classifier unit, for example an external sieve unit 420. Theexternal sieve unit 420 is fluidly coupled to discharge ports forstreams 422 and 421. In some aspects a gas distribution plate 406 may befluidly coupled to the main vessel body of system 400. In some aspectssystem 400 may include a cyclone 411 fluidly coupled to feed ports forstream 409 and discharge ports for streams 412, 410. In some aspectssystem 400 may include a control system 999 coupled to the components(illustrated or otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 4A, gaseous stream 402including one or more fluidization gases is provided to the hydratorsystem 400 through the bottom entry zone 413, also known as the plenumchamber, which is below the fluidization distribution plate 406. Gaseousstream 402 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 401 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 406 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 400 and as such it remains in thebubbling bed zone 407, unless discharged as stream 404. Stream 401 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 405 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 406. Stream 405 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 406 is designedto prevent backflow of any solids into the fluidization gas entry zone413. Solid material 405, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 407 and transported through the reactorfreeboard zone 408. The resulting mixed stream of fluidization gases andsolids is mixed-stream 409, and after leaving the reactor freeboard zone408, the stream 409 is sent to a cyclone 411, to separate the solids412, from the gases 410. The fluidization gas 402, is blown into thefluidization gas entry zone 413, of the fluidized bed reactor 400. Thisfluidizing gas 402, could be partially recycled from the gas stream 410leaving the cyclone 411. An external sieve unit 420 is used to segregatematerial withdrawn from the bubbling bed zone 407 based on physicalproperties, for example particle size. A portion of the materialnormally fluidized within the turbulent/transport regime may leave withthe material in the bubbling bed regime in stream 404.

In this implementation, the turbulent or transport regime material canbe separated from the bubbling regime material based on the differencein physical properties, using sieve unit 420 such that the smallermaterial drops through the sieve 420 and leaves as stream 421, and thelarger material remains above the sieve holes and leaves as stream 422.Stream 421 can be re-introduced into the reactor system 400 for furtherreaction, or combined with the finished circulating solids stream 412and sent to downstream processing, for example to cooling and/or limeslurry systems that can be used in carbon dioxide capture facilitiessuch as industrial (point source) facilities and facilities that capturemore dilute carbon dioxide sources such as direct air capturefacilities, as well as waste water treatment facilities or Kraft causticrecover processes. Stream 422 could also be sent to downstreamprocessing, for example to heat exchangers and fluid bed calcinersystems sometimes used in direct air capture facilities.

In some aspects, stream 421 may include for example calcium oxide andcalcium hydroxide particles, and stream 422 may include for examplecalcium carbonate pellets.

Referring to FIG. 4B, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 400. In some implementations, system 400 may include feed portsfor streams 401, 402, and 405 fluidly coupled to the main system 400,and a discharge port for stream 404 fluidly coupled to the main system400. In some aspects the discharge port 404 is fluidly coupled to aninternal solids classifier unit 430, which is internal to system 100. Insome aspects, the internal solids classifier unit 430 can be a cone andcap sloped stripper. In some aspects the internal solids classifier unit430 is fluidly coupled to a feed port for stream 431 and a dischargeport for stream 404. In some aspects a gas distribution plate 406 may befluidly coupled to the main vessel body of system 400. In some aspectssystem 400 may include a cyclone 411 fluidly coupled to feed ports forstream 409 and discharge ports for streams 412, 410. In some aspectssystem 400 may include a control system 999 coupled to the components(illustrated or otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 4B, gaseous stream 402including one or more fluidization gases is provided to the hydratorsystem 400 through the bottom entry zone 413, also known as the plenumchamber, which is below the fluidization distribution plate 406. Gaseousstream 402 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 401 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 406 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 400 and as such it remains in thebubbling bed zone 407, unless discharged as stream 404. Stream 401 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 405 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 406. Stream 405 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 406 is designedto prevent backflow of any solids into the fluidization gas entry zone413. Solid material 405, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 407 and transported through the reactorfreeboard zone 408. The resulting mixed stream of fluidization gases andsolids is mixed-stream 409, and after leaving the reactor freeboard zone408, the stream 409 is sent to a cyclone 411, to separate the solids412, from the gases 410. The fluidization gas 402, is blown into thefluidization gas entry zone 413, of the fluidized bed reactor, 400. Thisfluidizing gas 402, could be partially recycled from the gas stream 410leaving the cyclone 411. Componentry internal to system 400 is used tosegregate material withdrawn from the bubbling bed zone 407 based onphysical properties, for example particle size and/or density.

In this implementation, material is segregated based on physicalproperties such as size, and/or mass, through use of a baffled channelor annulus solids classifier component 430. Material from the bubblingbed zone 407 enters this component 430, and the baffles and upwardflowing gases from stream 431 prevent smaller or lighter particles frommaking it to the bottom discharge section and instead act to push thesmaller and/or lighter material back into the main vessel body of system400. The larger or heavier material moves down through component 430 tothe bottom discharge portion where it can then be discharged as stream404. In some aspects, stream 431 includes gases such as air or steam andthe like. In some aspects, component 430 may for example be a cone andcap sloped stripper. In other aspects, component 430 could be similar tothe mechanisms of discharging spent catalyst material from gas-solidfluidized beds, such as those found in fluidized beds used for catalyticcracking of hydrocarbons. In catalytic cracking fluidized beds, thespent catalyst solids are discharged, for example, from a fluidizedbubbling (non-circulating) bed via a baffled annulus such that largercatalyst moves downward and out into a discharge channel, and finermaterial and gases move upward back into fluidization vessel.

Referring to FIG. 5A, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 500. In some implementations, system 500 may include feed portsfor streams 501, 502, and 505 and fluidly coupled to the main system500, and a discharge port for stream 504 fluidly coupled to the mainsystem 500. In some aspects a gas distribution plate 506 may be fluidlycoupled to the main vessel body of system 500. In some aspects system500 may include a cyclone 511 fluidly coupled to feed ports for stream509 and discharge ports for streams 512, 510. In some aspects system 500may include heat tubing componentry 544 fluidly coupled to system 500,including a feed port for stream 549 and a discharge port for stream 550fluidly coupled to the heat tubing componentry 544. In some aspectssystem 500 may include a control system 999 coupled to the components(illustrated or otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 5A, gaseous stream 502including one or more fluidization gases is provided to the hydratorsystem 500 through the bottom entry zone 513, also known as the plenumchamber, which is below the fluidization distribution plate 506. Gaseousstream 502 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 501 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 506 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 500 and as such it remains in thebubbling bed zone 507, unless discharged as stream 504. Stream 501 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 505 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 506. Stream 505 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 506 is designedto prevent backflow of any solids into the fluidization gas entry zone513. Solid material 505, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 507 and transported through the reactorfreeboard zone 508. The resulting mixed stream of fluidization gases andsolids is mixed-stream 509, and after leaving the reactor freeboard zone508, the stream 509 is sent to a cyclone 511, to separate the solids512, from the gases 510. The fluidization gas 502, is blown into thefluidization gas entry zone 513, of the fluidized bed reactor 500. Thisfluidizing gas 502, could be partially recycled from the gas stream 510leaving the cyclone 511. heating tube componentry 544, has been added tothe vessel walls of system 500 in the bubbling bed zone 507.

In this implementation, any portions of either the sensible heat or heatfrom the hydrating reaction, which is not consumed to heat the pelletsand supply the enthalpy to bring the pellets to the operatingtemperature of the fluid bed, is used instead to make saturated steamfor subsequent superheat and power generation. In this implementation,The high temperature hydrator system 500 is built with heat tubingcomponentry 544 which lines the inner wall of the unit, within thebubbling bed zone 507. During operation of system 500, a stream 549which could be for example, boiler feed water another appropriate heatexchange fluid, or another process fluid stream, is fed into the tubecomponentry 544, where the heat from the fluidized bed zone 507 movesthrough the tubes and into the contents of stream 549 as they movethrough the tubes. In some aspects, stream 549 is boiler feed water andthis indirect heating converts the boiler feed water into saturatedsteam that leaves the tube componentry as stream 550. In some aspects,the saturated steam from these tubes is sent as stream 550 to downstreamheat consumers or power producers, for example other process heatexchangers or a steam superheater unit and/or steam turbine.

Referring to FIG. 5B, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 500. In some implementations, system 500 may include feed portsfor streams 501, 502, and 505 and fluidly coupled to the main system500, and a discharge port for stream 504 fluidly coupled to the mainsystem 500. In some aspects a gas distribution plate 506 may be fluidlycoupled to the main vessel body of system 500. In some aspects system500 may include a cyclone 511 fluidly coupled to feed ports for stream509 and discharge ports for streams 512, 510. In some aspects system 500may include heat tubing componentry 554 fluidly coupled to system 500,including a feed port for stream 555 and a discharge port for stream 556fluidly coupled to the heat tubing componentry 554. In some aspectssystem 500 may include a control system 999 coupled to the components(illustrated or otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 5B, gaseous stream 502including one or more fluidization gases is provided to the hydratorsystem 500 through the bottom entry zone 513, also known as the plenumchamber, which is below the fluidization distribution plate 506. Gaseousstream 502 may be, for example, air, steam or a combination of thesegases and their sub-components. Stream 501 is one of the solidfeedstocks, which enters the system above the fluidization distributionplate 506 and becomes fluidized in the bed or bubbling bed regimeswithin the fluidized bed system 500 and as such it remains in thebubbling bed zone 507, unless discharged as stream 504. Stream 501 may,for example, consist mostly of calcium carbonate or calcium oxide, andmay also consist in part of aqueous solutions such as liquid water.Stream 505 is the solid feedstock which becomes fluidized in theturbulent or transport fluidization regime and it also enters the systemabove the distribution plate 506. Stream 505 may, for example, consistmostly of calcium oxide or calcium carbonate and may also consist inpart of liquid or gaseous water. The distribution plate 506 is designedto prevent backflow of any solids into the fluidization gas entry zone513. Solid material 505, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 507 and transported through the reactorfreeboard zone 508. The resulting mixed stream of fluidization gases andsolids is mixed-stream 509, and after leaving the reactor freeboard zone508, the stream 509 is sent to a cyclone 511, to separate the solids512, from the gases 510. The fluidization gas 502, is blown into thefluidization gas entry zone 513, of the fluidized bed reactor 500. Thisfluidizing gas 502, could be partially recycled from the gas stream 510leaving the cyclone 511. The heat tube componentry 554 is positionedaway from the vessel wall of system 500, and instead is protrudingacross a substantial portion of the cross section of the bubbling bedzone 507. In this implementation, any portions of either the sensibleheat or heat from the hydrating reaction, which is not consumed to heatthe pellets and supply the enthalpy to bring the pellets to theoperating temperature of the fluid bed, is used instead to makesaturated steam for subsequent superheat and power generation. In thisimplementation, The high temperature hydrator system 500 is built withheat tubing componentry 554 which protrudes across a substantial portionof the cross section of the bubbling bed zone 507. During operation ofsystem 500, a stream 555 which could be for example, boiler feed wateranother appropriate heat exchange fluid, or another process fluidstream, is fed into the tube componentry 554, where the heat from thefluidized bed zone 507 moves through the tubes and into the contents ofstream 555 as they move through the tubes. In some aspects, stream 555is boiler feed water and this indirect heating converts the boiler feedwater into saturated steam that leaves the tube componentry as stream556. In some aspects, the saturated steam from these tubes is sent asstream 556 to downstream heat consumers or power producers, for exampleother process heat exchangers or a steam superheater unit and/or steamturbine.

Referring to FIG. 6, calcium oxide conversion to calcium hydroxide inthe presence of a fluid bed is described with respect to illustrativesystem 600. In some implementations, system 600 may include feed portsfor streams 601, 602, and 605 and fluidly coupled to the main system600, and a discharge port for stream 604 fluidly coupled to the mainsystem 600. In some aspects a gas distribution plate 606 may be fluidlycoupled to the main vessel body of system 600. In some aspects system600 may include a cyclone 611 fluidly coupled to feed ports for stream609 and discharge ports for streams 612, 610. In some aspects system 600may be fluidly coupled to an external fluidized bed system 660,including discharge ports fluidly coupled to the external fluidized bedsystem 660 for streams 621, 665 and feed ports for stream 620 and 663.In some aspects system 600 may be fluidly coupled to a feed port forstream 665. In some aspects, the external fluidized bed system 660 maybe fluidly coupled to heat tubing componentry 668 and system 660 andheat tubing componentry 668 may also be fluidly coupled to a feed portfor stream 661 and a discharge port for stream 664. In some aspectssystem 600 may include a control system 999 coupled to the components(illustrated or otherwise).

In some implementations, fluidization gases include, for example, air,steam, and the like. As depicted in FIG. 6, gaseous stream 602 includingone or more fluidization gases is provided to the hydrator system 600through the bottom entry zone 613, also known as the plenum chamber,which is below the fluidization distribution plate 606. Gaseous stream602 may be, for example, air, steam or a combination of these gases andtheir sub-components. Stream 601 is one of the solid feedstocks, whichenters the system above the fluidization distribution plate 606 andbecomes fluidized in the bed or bubbling bed regimes within thefluidized bed system 600 and as such it remains in the bubbling bed zone607, unless discharged as stream 604. Stream 201 may, for example,consist mostly of calcium carbonate or calcium oxide, and may alsoconsist in part of aqueous solutions such as liquid water. Stream 605 isthe solid feedstock which becomes fluidized in the turbulent ortransport fluidization regime and it also enters the system above thedistribution plate 606. Stream 605 may, for example, consist mostly ofcalcium oxide or calcium carbonate and may also consist in part ofliquid or gaseous water. The distribution plate 606 is designed toprevent backflow of any solids into the fluidization gas entry zone 613.Solid material 605, any associated reaction products and any steamgenerated from liquid water content present in the system are carriedout of the bubbling bed 607 and transported through the reactorfreeboard zone 608. The resulting mixed stream of fluidization gases andsolids is mixed-stream 609, and after leaving the reactor freeboard zone608, the stream 609 is sent to a cyclone 611, to separate the solids612, from the gases 610. The fluidization gas 602, is blown into thefluidization gas entry zone 613, of the fluidized bed reactor 600. Thisfluidizing gas 602, could be partially recycled from the gas stream 610leaving the cyclone 611. An indirectly heated external fluidized bedsystem 660 is connected to system 600 such that material from thebubbling bed 607 can be discharged to the external fluidized bed system660 and after being processed in 660, the material can be sent back tosystem 600. The separate fluidized bed vessel 660 may includecomponentry such as heat tubing 668, heat exchange medium entering theheat tubing 668 as stream 661 and leaving as stream 664, a denselyfluidized bed 667, and a fluidization gas stream 663.

In some implementations, system 660 is operated under significantlyhigher density bed conditions so that heat tubing 668 can be denselypacked within the vessel 660 and come in close contact with thefluidized pellet bed 667.

In some implementations, the pellets from the bubbling bed zone 607 ofthe main high temperature hydrator vessel 600 may be moved back andforth between vessel 660 and vessel 600 in order to exchange heat fromvessel 600 to vessel 660 and its componentry, for example the heattubing system 668.

In some implementations, steam generation may be split between the hightemperature hydrator system 600 and the external dense fluidized bedvessel 660. In this implementation, a portion of the discharged stream604 would feed into system 660 as stream 620. Both boiler feed waterheating and steam generation could occur within the tubing 668, and theresultant cooled pellet material is transferred back to system 600 viastream 665. In some aspects, the heat exchange occurring within system660 is such that stream 665 is cooled to below 300° C. and is recycledto the bubbling bed zone 607. In some aspects, sending the cooler stream665 back to system 600 allows for control of temperature within system600.

In some aspects, there is another portion of stream 604 that does notfeed into system 660, but instead leaves as stream 621. This stream 621could be sent to downstream processing, for example to a fluidizedcalciner unit as part of a direct air capture system.

In some implementations, system 600 might be configured such that itproduces a low bed-side heat transfer film coefficient. This, combinedwith heat transfer surface mechanical limitations, for example, a lowheat tube surface area to bed surface area ratio, might not allow forfull heat extraction from the bubbling bed zone 607 in system 600.

In some aspects heat coils are used inside system 600, where the heatcoils are as illustrated in FIGS. 5A and 5B. In some of these cases, thefluid in the streams feeding the heat coils is boiler feed water and thetemperature of the boiler feed water, may not provide enough of adifferential temperature drive to overcome the above mentionedmechanical surface area limitations (that result in a low approachtemperature requirement). In these cases, the use of an external denselyfluidized bed system such as 660 as illustrated in FIG. 6, would utilizea lower fluidization velocity (resulting in a denser bubbling bed, forexample) in comparison to the bubbling bed in system 600, and as suchshould have both a higher surface area ratio and bed-side coefficient toovercome the low boiler feed water approach temperature requirements.

FIG. 7 illustrates how a high temperature hydrator may, for example, beconnected to other processes such as a direct air capture process. Insome implementations, the direct air capture (DAC) process is configuredto capture dilute concentrations of carbon dioxide from the atmosphereand produce a concentrated liquid or gaseous stream of carbon dioxidewhich can be utilized in applications such as Enhanced Oil Recovery(EOR), as feedstock for the production of synthetic hydrocarbons. Insome cases, the concentrated liquid or gaseous carbon dioxide caninstead be sequestered in a subsurface saline aquifer, reservoirs oraging oil fields as part of the previously mentioned EOR process. Insome cases, the concentrated liquid or gaseous stream of carbon dioxidemay instead be combined with other chemical feedstock, for examplehydrogen, and further processed into a synthetic hydrocarbon such asdiesel, gasoline and waxes.

In some implementations, the DAC process operates as a continuous,closed-loop system that inputs water, energy and small material make-upstreams, and delivers highly concentrated, pressurized carbon dioxide.

Some examples of major process equipment involved in an implementationof this type of direct air capture commercial process include aircontactors, fluidized bed reactive crystallizers also known as pelletreactors, oxy-fired circulating fluidized bed calciners, and some typesof lime slakers or hydrators. Auxiliary equipment also involved in thistype of direct air capture process may include, for example,compressors, turbines, boilers, heat exchangers, steam systems andoxygen production units such as Air Separation Units (ASU) or a varietyof water electrolyzer units.

In some implementations, the DAC process draws air through an aircontactor, where it contacts a strong aqueous hydroxide solution, suchas potassium hydroxide (KOH). The carbon dioxide in the air reacts withthe potassium hydroxide to form a solution of potassium carbonate(K₂CO₃) and water, absorbing about three-quarters of the availablecarbon dioxide.

In some implementations, the DAC process potassium carbonate solution istransferred to a fluidize bed reactive crystallizer or pellet reactor.In some aspects the fluidized bed reactive crystallizer or pelletreactor is a liquid-solid fluidized bed, where the potassium carbonatesolution can contact calcium hydroxide (Ca(OH)₂), also known as hydratedlime, and precipitate calcium carbonate pellets through a process knownas causticization.

In some implementations, the DAC process calcium carbonate pellets fromthe fluidized bed reactive crystallizer pass through a slaker to absorbheat before being fed into a circulating fluidized bed calciner, whichis essentially a type of high-temperature kiln or furnace. The heatreleases the carbon dioxide as a highly concentrated, gaseous stream,leaving calcium oxide (CaO) as by-product, through a process known ascalcination. In some aspects, heat for the calciner is provided bycombusting natural gas with oxygen (known as “oxy-firing”), so that thecombustion exhaust may contain mostly carbon dioxide with some water,and can be combined with the carbon dioxide stream leaving the calciner.In some aspects the oxygen used for oxy-firing is separated from airusing an air separator.

In some implementations of the DAC process, the calcium oxide is fedinto the slaker, where it may combine with steam to regenerate hydratedlime, which can then be fed into the fluidized bed reactive crystallizeror pellet reactor for reuse. In some aspects, the slaker may beconfigured as a high temperature hydrator.

In some implementations, at least a portion of the electrical power forthe DAC process derives from on-site generation. In some aspects, theon-site power generation uses natural gas as fuel, or from external,grid-supplied renewable electricity sources. In some aspects, some ofthe DAC process electrical power is generated on-site using waste orexcess steam, for example from the calciner or high temperaturehydrator.

FIG. 7 does not show all the major equipment involved in a direct aircapture process, rather, it illustrates one embodiment of how the keyinterfaces, for example heat and material stream exchanges, could be setup between a high temperature hydrator system and the immediate upstreamand downstream process and heat exchange equipment of a direct aircapture process. In the implementation illustrated in FIG. 7, calciumcarbonate pellets, which may have been processed upstream to removeprocess solution, are fed, slightly wet, via stream 700 to the hightemperature hydrator unit 740. In some aspects the direct air captureprocess may include a control system 999 coupled to the components(illustrated or otherwise).

The wet calcium carbonate pellets in stream 700, and hot calcium oxide(quicklime) in stream 710 that originated from the calciner system 800,are both fed into the high temperature hydrator unit 740 and mixed. Thehigh temperature hydrator 740 is fluidized by recirculating steam, asstream 705. In some aspects, a portion of the steam stream 705 takespart in the slaking reaction that converts the feed stream of calciumoxide material in stream 710 into calcium hydroxide material.

The calcium carbonate pellets in stream 700 that are fed into the hightemperature hydrator unit 740 do not participate in the slakingreaction; instead, they are dried and heated using the process heatwithin the high temperature hydrator unit 740. The calcium oxide instream 710 is delivered at a temperature of approximately 694° C. Thecalcium oxide stream 710 may include, for example, approximately 94.5%reactive calcium oxide, 3.4% unreactive calcium oxide, and 2.1%impurities.

A stream of mostly preheated and dried pellets are drawn out of thebubbling bed zone of the high temperature hydrator unit 740 and sent asstream 708 to the solid sieve unit 760 to separate the solids into astream of larger pellets, stream 719, and any smaller particles, such ascalcium oxide and calcium hydroxide, as stream 709. The larger solids instream 719 can be fed to the calciner preheat cyclone system 790 at anapproximate temperature of 300° C.

The calcium hydroxide solid particles can be separated from the calciumcarbonate pellets due to a substantial size difference between thesmall, micron sized calcium hydroxide particles and the larger,millimeter sized calcium carbonate pellets. The calcium hydroxide willtherefore pass through the solid sieve unit 760, which may for examplehave a mesh with 0.8 mm diameter holes, while the pellets, being larger,will not pass through the holes in the mesh and will instead move alongthe top of the mesh and out a separate exit. Any unreacted calcium oxidepresent in the feed stream to the solid sieve unit 760 will, dependingon size, either recycle back to the calciner unit 800 with stream 719 orcontinue onto the cooler unit 750 in stream 711, where it has anotheropportunity to react with water, in a hydration reaction, to formcalcium hydroxide.

After passing through the high temperature hydrator unit 740, the steamstream 701 may be further cleaned of solids using for example a cycloneunit 765 and a baghouse unit 770, then recirculated back to the inletgas distributor, or “windbox,” of the high temperature hydrator unit 740using a high temperature blower 820.

Any solid material that passes the primary cyclone of the hightemperature hydrator unit 740 will be fine particles that may becaptured further downstream by a cyclone unit 765, leaving this unit asstream 706 or even further downstream in a baghouse unit 770, leavingthis unit as stream 707.

In some implementations, a portion of the calcium carbonate pellets maybe small enough to transport along with the circulating material and assuch, wind up in any one or a combination of streams 706, 707, and 709.Depending on the amount of calcium carbonate pellet material present inthese streams, this may introduce a form of dead load propagatingforward into downstream processes within the system. This dead load canbe mitigated by including, for example, one or more hot sieve screens toprocess at least a portion of one or both of streams 706 and 707 tocapture the calcium carbonate material and direct it over to thecalciner system 800.

In some implementations, all three streams 706, 707, and 709, could becombined into stream 711 and sent to a cooler unit 750, where they arecooled using water from streams 715 and 718. In some aspects, coolingunit 750 is built with a cooled screw, where stream 718 is boiler feedwater from a steam condenser unit 745 that flows through an internalcavity in the screw, allowing for indirect cooling of the contents ofthe cooling unit 750. This screw may mix stream 711 with a water stream715. In some aspects, stream 711 may include for example unreactedcalcium oxide, which as a result of mixing in cooling unit 750 withstream 715, could react via the hydrating reaction to produce calciumhydroxide. In some aspects, unit 750 also allows some heat from stream711 and some heat resulting from any hydrating reaction to transferindirectly to the boiler feed water stream 718, providing a furtherpreheated stream 712 of boiler feed water that can then be sent to thehigh temperature hydrator unit 740 for conversion into saturated steamstream 703.

In some implementations, the cooler unit 750 carries out two functions:a) it cools exiting stream 716 to below 100° C. so that it can be safelymixed with water in mixing tank 755 to form the required Ca(OH)₂ slurryand b) it provides for a small amount of water (stream 715) to besprayed onto the solid Ca(OH)₂ to complete the remaining slakingreaction.

In some implementations, after leaving the cooler unit 750, the Ca(OH)₂stream 716 is sent to the mixing tank 755, where it is formed into aslurry mix using a water source (stream 714). This slurry mix could be,for example, diluted with water to a slurry having a consistency ofbetween 20 wt % to 40 wt % solids. In some aspects, the water source maybe for example potable, non-potable, process water knocked out fromon-site compressor units, recovered from washing systems or otherprocess units.

In some implementations, the cooled Ca(OH)₂ that is now retained withinunit 755 can be sent further downstream to other processes that requirethe use of hydrated lime in either solid Ca(OH)₂ form or a wetter slurryform. Examples of some types of downstream processes that may be fedfrom stream 717 include the pellet reactor units found within some typesof carbon dioxide capture processes such as direct air capture, watertreatment facilities, and caustic recovery units within the Kraft pulpand paper process.

In some implementations, the heat generated in the high temperaturehydrator 740 may not be fully consumed in the process of drying andpreheating the pellets. The excess heat could be used to generate steam,which could then be use for example for other process heat requirementsor for power production via stream 703, which in the implementationshown in FIG. 7, feeds into a steam superheater unit 785. In otheraspects, the excess heat from the high temperature hydrator 740 could beremoved from unit 740 by means of direct exchange with internal fluidswithin unit 740 that then leave the unit and are fed through downstreamheat exchangers (not shown). In other aspects, the excess heat from thehigh temperature hydrator unit 740 could be removed by means of indirectexchange with heating tubes or coils located either within the vesselwalls of 740 as shown in FIG. 7, or for example by heat tubes or coilslocated further into the bubbling bed zone of unit 740 as illustrated inFIG. 5B, or via a separate external fluidizing vessel as illustrated inFIG. 6.

In some aspects, the oxy-fired calciner 800 is a circulating fluidizedbed, which is fluidized with a flow of pure oxygen shown in the processflow diagram of FIG. 7 as stream 723.

The calciner 800 is used to decompose the calcium carbonate (CaCO₃)pellets from stream 719 into calcium oxide (CaO) and carbon dioxide at atemperature of approximately 900° C. High temperature is required todrive the endothermic calcination reaction to the desired 98% conversionof calcium carbonate to calcium oxide.

The hot pellets from the high temperature hydrator 740 are sent to thecalcination system via stream 719 by way of two consecutive cyclonepreheat stages (790 followed by 795) to raise the temperature of thepellets further before entering the calciner unit 800 via stream 721.

Hot gas from the calciner unit 800 output stream 725 (primarily carbondioxide), is fed to preheating cyclone stage 795 at approximately 900°C., and then via stream 726 to preheat cyclone stage 790 atapproximately 650° C. The gas stream 727 is then extracted from thecalciner unit 800 and may be sent through coolers such as unit 785before being sent to clean-up units such as 775 and compression unit815.

The gas leaving the calciner 800 in stream 727 contains all the carbondioxide from the calcination of the pellets. In some implementationswhere for example natural gas combustion is used as the heat to drivethe endothermic calcination reaction, stream 727 would also contain thecarbon dioxide from the combustion of natural gas. In some aspects, thecomposition of this gas stream 727 is 82.8 wt % CO₂, 14.6 wt % H₂O, 1.13wt % O₂, and 1.43 wt % N₂.

In some aspects, a small amount of the calciner 800 off-gas (primarilycarbon dioxide) is re-circulated back into the system through stream 734after passing the last cooling unit 785, but before the water vapor hasbeen removed. This stream can be used as a supply for various minorfluid bed requirements such as instrument purges, and to aid thecirculation of the solids from the primary cyclone 795 back into themain calciner bed. This can be done with air but recycled carbon dioxideis used in this implementation instead to prevent dilution of thecalciner off-gases with nitrogen.

The stream 739 of remaining hot solid reaction product leaving calcinerunit 800—which includes for example mostly quicklime or calcium oxide(CaO)—may be used to preheat the incoming oxygen feed stream 722 via aheat exchange unit 805 before being sent to downstream cooling and/orprocessing units. This solid calcium oxide product from the calcinationreaction is shown as stream 739 in FIG. 7. In some implementations, thevery hot material in stream 739 may be close-coupled to the hightemperature hydrator unit 740 to avoid an expensive transport device.This may also require, for example, a grade level high temperaturehydrator pellet screen with a vertical 300° C. pellet pneumatictransport to carry the pellet feed (stream 719) to the calciner pre-heatcyclone 790. In some aspects it is desirable to minimize, for example,capital expense and operational difficulties of this configuration; inthis case, a portion of the supplemental (in addition to feed pelletwater) reactive steam (stream 729), could be diverted as a slipstreamand used for the pneumatic transport of stream 719 to the pre-heatcyclone 790, before being returned to the recirculation stream 704 (notshown).

In some aspects, unit 805 could be a bubbling fluidized bed. In someaspects where unit 805 is a bubbling fluidized bed, the hot calciumoxide in stream 739 from the calciner unit 800 is fluidized by theoxygen stream 722, which could transfer heat directly from the calciumoxide stream 739 to the oxygen stream 722. This could raise thetemperature of the oxygen stream 722 from ambient to approximately 700°C. in stream 723. In some aspects this bubbling fluid bed 805 may berefractory lined, suitable for service with high temperature oxygen, andcompletely gas-tight to prevent release of oxygen from the system.

In some aspects, the heat for the calciner unit 800 is supplied bycombustion of natural gas fed from stream 724.

The heat for the calcination endothermic reaction could be provided froma variety of sources, depending on the economics and resourcesassociated with the location of a particular commercial plant. In anexample aspect, the heat source is electric. In another example aspect,the heat source is combustion of a hydrocarbon such as natural gas. Inanother example aspect, the heat source is solar or solar thermal. Inanother example aspect, the heat source is combustion of biomass. In yetanother example aspect the heat source is combustion of hydrogen.

Oxygen for the calciner unit 800 is provided via stream 722. In someaspects, the oxygen stream 722 is supplied by an air separation unit(ASU) which may for example operate at a pressure of approximately 20kPa_(g). In other aspects the oxygen source for stream 722 may be aby-product of water electrolysis.

In some implementations, the high temperature hydrator unit 740 may bebuilt as a refractory lined circulating fluidized bed, or CFB. In someaspects, the fluidization velocity in the high temperature hydrator ischosen such that the calcium carbonate pellets remain as a fluidized bedin the bottom of the device while smaller calcium oxide particlesrecirculate through the primary cyclone and loop seal that are shown asbeing integral to unit 740 in FIG. 7 and which are called out in moredetail in FIG. 3B. As the calcium oxide particles are transported aroundthe high temperature hydrator 740, they may react with the steam andslake to form Ca(OH)₂ and, as a result of this reaction, heat may bereleased. The sensible heat of the circulating calcium oxide material,fluidization gases, and the heat from the hydrating reaction contributeto heating the calcium carbonate pellets in the bubbling bed zone up to300° C. The heated and dried pellets (708) are drawn out of the bubblingzone of the high temperature hydrator unit 740 and sent to downstreamprocesses. Any fine material which passes the primary cyclone of thehigh temperature hydrator unit 740 may be, for example, Ca(OH)₂ andcould be captured by the cyclone (765) and/or baghouse (770) units.These units may be used If the downstream high temperature fluidizationfan (820) is not able to withstand the small amount of solids in therecirculating steam stream 704. All three streams of hydrated lime (706,707, 709) may be combined as stream 711 and sent to another unit in theprocess, for example a cooling unit 750 as illustrated in FIG. 7.

In one aspect, heat generated in the high temperature hydrator unit 740shown in FIG. 7 may not be fully consumed in drying and preheating thecalcium carbonate pellets; in this case, the excess or waste heat couldbe used to generate steam for other heat or power requirements. Oneexample of how this could be done is illustrated in FIG. 7, wheresuperheated steam stream 703 is produced indirectly by flowing boilerfeedwater as part of stream 712 through a set of heating coils imbeddedin the high temperature hydrator unit 740. This steam leaves the hightemperature hydrator 740 as stream 703, is sent to a steam superheaterunit 785 where it is further heated and then used to feed a steamturbine 780.

In another implementation, the high temperature hydrator unit 740 asillustrated in FIG. 7 may be operated such that the fluidizationvelocity within this unit 740 is set as high as possible while keepingthe calcium carbonate pellets in a bubbling fluidized bed mode. In anexample aspect, this fluidization velocity is set to 0.75 m/s. At Thisvelocity, the calcium oxide will be elutriated out of the bed, capturedby the primary cyclone and re-introduced back into the bed via therecirculation leg. In some aspects this recirculation leg may be asshown in FIG. 4B and may include for example a loop seal. In thisimplementation the calcium oxide material could behave as a circulatingfluid bed while the calcium carbonate pellets behave as a back mixedbubbling fluid bed. There is a recirculating flow of steam, stream 705,which is used to fluidize the bed. Upon leaving the high temperaturehydrator unit 740, the steam stream 701 goes through a dust collectionsystem, which may include for example a baghouse unit 770 and/or cycloneunit 765 to remove any calcium oxide and calcium hydroxide particlesfrom the steam stream before being sent to a high temperature fan 820which then boosts the stream pressure for reintroduction into thefluidized bed.

In some implementations, in addition to any water carried into the hightemperature hydrator unit 740 along with the pellet stream 700, someadditional steam is necessary to convert 85% of the quicklime tohydrated lime via the hydrating reaction,CaO_((s))+H₂O_((g))→Ca(OH)_(2(s))+105.2 kJ

In some aspects of this implementation, the additional steam can beprovided by pulling a low pressure steam stream 729 off of a turbine 780(as shown in FIG. 7) and injecting this stream 729 into the fluidizingsteam flow after it has passed through the high temperature baghouseunit 770. In some other aspects, the additional water needed to completethe above hydrating reaction could be directly injected into streams 704or 705 as liquid water (not shown).

The choice between feeding water into the recirculating steam loop andusing low pressure steam from the steam turbine 780 is determined by theeconomic trade-off between the additional energy generated by having theextra steam flow through the steam turbine 780, and the additionalcapital and operating costs of generating extra boiler feed water andprocessing the extra steam.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims. Further modifications and alternative embodiments of variousaspects will be apparent to those skilled in the art in view of thisdescription. Accordingly, this description is to be construed asillustrative only. It is to be understood that the forms shown anddescribed herein are to be taken as examples of embodiments. Elementsand materials may be substituted for those illustrated and describedherein, parts and processes may be reversed, and certain features may beutilized independently, all as would be apparent to one skilled in theart after having the benefit of this description. Changes may be made inthe elements described herein without departing from the spirit andscope as described in the following claims.

What is claimed is:
 1. A method comprising: transferring at least one feed stream comprising calcium oxide, calcium carbonate, water, and a fluidizing gas into a fluidized bed; contacting the calcium oxide with the water; based on contacting the calcium oxide with the water, initiating a hydrating reaction; producing, from the hydrating reaction, calcium hydroxide and heat; transferring a portion of the heat of the hydrating reaction to the calcium carbonate; and fluidizing the calcium oxide, calcium hydroxide, and the calcium carbonate into a first fluidization regime and a second fluidization regime, the first fluidization regime comprising at least a portion of the calcium carbonate and at least a portion of the calcium oxide, the second fluidization regime comprising at least a portion of the calcium hydroxide and at least another portion of the calcium oxide, the first fluidization regime different than the second fluidization regime.
 2. The method of claim 1, wherein the second fluidization regime comprises another portion of the calcium carbonate.
 3. The method of claim 1, wherein fluidization takes place using at least one fluidization velocity, the at least one fluidization velocity sufficient to cause the at least a portion of one of the calcium carbonate, calcium hydroxide or calcium oxide to separate from the at least a portion of the other calcium carbonate, calcium hydroxide or calcium oxide into the first and second fluidization regime.
 4. The method of claim 1, wherein the first and second fluidization regimes comprise a bubbling bed regime and at least one of a transport or turbulent regime.
 5. The method of claim 4, further comprising: fluidizing at least a portion of the calcium carbonate in the bubbling bed regime; and fluidizing at least a portion of the calcium hydroxide in the transport or turbulent fluidization regime.
 6. The method of claim 1, wherein the fluidizing gas comprises steam.
 7. The method of claim 4, further comprising: recirculating a portion of at least one of the calcium oxide or the calcium hydroxide in the transport or turbulent fluid regime back into the fluidized bed; and based on the recirculating, increasing a residence time of at least one of the calcium oxide or calcium hydroxide in the fluidized bed.
 8. The method of claim 1, further comprising: generating steam from excess heat; and circulating the generated steam to provide heat or power to the at least one of a downstream heat consumer or power producers.
 9. The method of claim 1, further comprising providing the water from at least one of a steam feed, a liquid water feed, or water from a wet calcium carbonate feed.
 10. The method of claim 1, further comprising recirculating the fluidization gas that exits a fluidized gas outlet of the fluidized bed to a fluidization gas inlet of the fluidized bed.
 11. The method of claim 1, wherein the method is part of a caustic recovery process.
 12. The method of claim 11, wherein the caustic recovery process is part of at least one of a direct air capture process, a carbon dioxide capture process, or a pulp and paper process.
 13. The method of claim 1, wherein at least a portion of one of calcium carbonate, calcium oxide or calcium hydroxide are separated into at least two different fluidization regimes based on one or more of physical properties of the calcium carbonate, calcium oxide, or calcium hydroxide.
 14. The method of claim 13, wherein the one or more physical properties comprises at least one of density, particle size or shape.
 15. The method of claim 1, further comprising at least one of heating or drying the calcium carbonate with at least one of a sensible heat of the calcium oxide or the produced heat of the hydrating reaction.
 16. The method of claim 1, wherein each of the calcium oxide, the calcium carbonate, the water, and the fluidizing gas are transferred into the fluidized bed in a separate feed stream.
 17. The method of claim 1, wherein the calcium oxide and at least a portion of at least one of the water or the fluidizing gas are transferred into the fluidized bed in a first fluid stream, and the calcium carbonate and at least a portion of at least one of the water or the fluidizing gas are transferred into the fluidized bed in a second fluid stream that is separate from the first fluid stream. 